Periglacial features developed on the exposed lake bottoms of seven lakes that drained rapidly after 1950, Tuktoyaktuk Peninsula area, western Arctic coast, Canada

摘要: A variety of periglacial features have been studied on the exposed bottoms seven lakes that drained rapidly after 1950 in Tuktoyaktuk Peninsula area, western Arctic coast, Canada. Ice-wedge growth commenced as early first winter following drainage. In most areas, ice-wedge cease within several decades, because and spread vegetation which resulted snow entrapment increased ground temperatures. At sites where thermokarst lake enlargement had transgressed across terrain with polygons, reactivated polygon patterns developed some pre-drainage shallow water former troughs becoming ridges. Excavations ridges extensive differential frost heave, cryoturbations, slickensided vertical shear planes. Many collapse pits heave between silts sands, cavity formation beneath frozen silts, infilling adjacent sand late summer. Other developed, either subaqueously prior to drainage or subaerially Underground flow has observed, summer, a near-surface layer ice-rich was underlain by desiccated active sands at temperature well below 0°C. there underground loading escape appear during thaw period. Copyright © 1999 John Wiley & Sons, Ltd. Un grand nombre de phenomenes periglaciaires divers ont ete etudies sur les fonds sept lacs qui rapidement draines apres dans la peninsule (delta du Mackenzie, Canada). La croissance coins glace commence des le premier hiver suivi Dans majorite cas, cesse en quelques decades suite eu pour effet retenir neige et d'augmenter sol. Aux endroits ou l'elargissement lac thermokarstique s'etait etendu terrains contenant polygones glace, reseaux reactives se sont developpes eaux etaient peu profondes avant drainage, fosses y correspondaient devenus rides. Des excavations au travers ces reliefs montre soulevements differentiels extensifs, cryoturbations plans verticaux cisaillement. De nombreuses d'effondrement developpees entre sables, cavites sous geles remplissage vides par sables voisins fin l'ete. D'autres effondrements apparus, fois eau d'une facon subaerienne Un ecoulement souterrain observe debut l'ete une bien inferieure 0°C, quand couche riche proche surface s'est trouvee desseches active. En il un souterrain, mouvements densite lieu echappements d'eau produits pendant degel. Ltd.